Electrogenic Fish

To keep a balance among living things in the natural world, there have to be many ways for animals to get food. In lakes, oceans, and rivers this is especially difficult because of the amount of cover that exists in which small fish can hide. If small fish over-populate, they exceed their food supply and the whole ecosystem collapses. One way to keep balance is with a predator that is an electrogenic fish.

One of the agents designed into the ecological system is the existence of living things that send out electrical charges. Very little is understood about how this works, but new data is enabling us to understand how cleverly electrogenic fish are designed to enable them to find and eat forage fish.

The January/February 2018 issue of Popular Science (page 75) has an interesting article by Ken Catania, a professor of neurobiology at Vanderbilt University on his studies of electric eels. What he found is that when an electric eel discharges a high-voltage pulse, the nerve fibers in nearby animals are affected. If a small fish is swimming near the eel, it becomes frozen like a statue long enough for the eel to catch it. Even more interesting is the fact that the eel can make any creature that is nearby twitch when the eel fires off a blip of current. The eel can swim up to a clump of seaweed and fire off a pulse. Anything hiding in the seaweed, like a small fish, will reveal its presence by twitching.